Puerto Rican older adults living in the US mainland have been identified as a group highly at-risk of excess chronic conditions, particularly diabetes, depression, and physical impairment. Few studies have been conducted on this rapidly growing and generally low-income ethnic group. To reduce health disparities, it is necessary to understand the factors that combine to progress to poor health outcomes. The overall aim of the proposed Center is to perform a series of inter-related studies involving a cohort of older adults of Puerto Rican origin to evaluate specific stressors affecting the Puerto Rican community, and to determine the effect of these stressors on allostatic load and, in turn, on disease specific outcomes. The Center will include 5 research projects: Project 1: Prospective (2 y) cohort study. We will investigate both baseline and 2 year prospective associations between psychosocial stressors and allostatic load; and in turn, allostatic load and functional decline, specifically depression, cognitive decline and physical disability; along with the role of social support, and vitamin intake and status in modifying, these associations. Project 2: Sociological investigation ofpsychosocial stressors and their measurement. U_ _;,g both qualitative and quantitative methodology, we will gain contextual understanding of the sources of stress in this population that relate to aUostatic load, and will adapt instruments for its measurement. Project 3: Intervention studies. Using subsets of the baseline study, we will investigate the effectiveness of three different 2 y interventions in reducing indicators of allostatic load. Each is designed to be feasible for expansion by community agencies if effective. These include: 1) vitamin supplementation; 2) food coupons and nutrition education; and 3) social support and participation. Project 4: Investigation of genetic contributions to allostatic load. We will explore the relationship between selected gene variants and allostatic load, at baseline and with change over time; and will investigate the interaction between gene variants and responses to the differing nutrition and social interventions. Project 5: In-depth investigation of the mechanisms of inflammation. In a subset of the cohort that overlaps with those participating in interventions, we will assess detailed markers of inflammation and examine cellular response to acute stress. Three cores will work with all projects, including administrative, statistical and laboratory cores. A pilot grants program during years 2-4 will encourage additional investigations relevant to the Center theme.